Find your user ID by clicking on your name and navigating to any of the subsections (Followers/Following/My Playlists/Settings). Your user ID is the number in the URL, e.g. 17601867 for the URL http://songza.com/user/17601867/following.

I've updated Flickr Original for Firefox 4.0.x and Safari:
- Now works with photostream images (Flickr recently added spaceball.gif images over all photostream images).
- Selecting "Download" no longer opens a new tab.